The evening before smoking, pat your turkey dry with paper towels, remove neck and giblets, and loosen skin on breasts from the meat. I tend to take this time to bond with my poultry and decide what name they would like to be called while we get to know one another over the next day.
Mince 4 cloves garlic and the tarragon, parsley, zest of the lemon (reserving the lemon).
Use a mortar and pestle if possible to combine the ingredients to make a paste. Add 1-2 tbsp salt and 1 tbsp pepper and the olive oil. Rub the mixture all over the turkey, under the skin, making sure to cover the wings, legs and bottom.
Chop the lemon in half and the remaining garlic in half and place it in the cavity. Tie the legs together and tuck the wings under the turkey and place in an aluminum pan in the fridge overnight.
Soak your wood chips. I used apple for this because it's what I had, but hickory or mesquite would go well.
The morning of, prep your smoker for 200 to 225 degrees. Put water in the pan and have everything ready to go.
Mold the butter into a large 2" ball and press gently onto the turkey breast to secure. Cover with aluminium foil and gently slice a hole directly into where the butter ball is. This is to help create a steam pocket and circulate the smoke. (I too was nervous about wrapping my boy in aluminum foil, but it worked. Trust me). Poke a hole in the bottom of the pan (to allow draining of fluids) and place in the slow cooker.
Add more wood after 1 hour of cooking and again one last time after 2.
Allow the turkey to smoke until it reaches an internal temp of 170 at it's thickets point. It took 6 hours for my 12.5 lbs turkey. If the skin is not getting a rich smoked color, remove the aluminum foil for the last hour of cooking.
Carefully remove the turkey from the smoker ( I used a heavy duty sheet pan to stabilize the aluminum pan while transporting) cover and let rest for 20 minutes before slicing to serve.